The present disclosure relates to medical implants. More particularly, the present disclosure relates to medical implants having a mesh configuration that are useful in tissue repair.
Implantable meshes may be inserted into a patient's body during a surgical procedure to reinforce, at least temporarily, deficient musculo-aponeurotic substrates. For example, implantable meshes may be utilized to treat hernias, urinary incontinence, uterovaginal prolapses, and other similar injuries.
Implanted meshes may be produced from non-absorbable or absorbable materials and may be constructed of monofilament threads or multifilament yarns. Some commercially available implantable meshes are made of monofilaments threads, the resulting mesh having relatively small pores, in some cases less than about 1 mm, and almost all are relatively rigid. This rigidity results in a mechanical mismatch between the implant and the host tissues which, in turn, may result in irritation of the tissue at the site of the implant. This irritation, combined with a lack of porosity, may lead to the formation of a pseudo fibrous capsule around the mesh implant which may cause discomfort, chronic pain, and increase the risk of recurrence.
Recently, some monofilament polypropylene meshes have been demonstrated to be oxidized in vivo when infection or acute inflammation occurs, resulting in some degradation of the material which could also be responsible for mesh stiffening, impaired abdominal wall movement when used to repair a hernia, and chronic pain.
Multifilament meshes are usually softer and more compliant than monofilament meshes. A multifilament mesh may possess a larger, more developed surface, which could be beneficial with respect to tissue integration, but could be detrimental with respect to increased bacterial contamination.
One way to attempt to minimize the risk of infection associated with the use of meshes in vivo is to apply antimicrobial coatings thereto. For example, U.S. Patent Application Publication No. 2005/0085924 and U.S. Pat. No. 5,217,493 both disclose meshes with coatings possessing antimicrobial agents. However, while these meshes may exhibit an antibacterial effect on a local and diffuse basis by inhibiting bacterial adhesion and proliferation as a result of the antibiotics and antiseptics included in the coatings, they may also damage the cytocompatibility of the material, thereby inhibiting and/or delaying the integration of the mesh with tissue. This inhibition or delay of the integration of the mesh material may generate adverse effects such as local necrosis, seroma, pseudocapsule formation, secondary infection, and the like.
Meshes with long term biocompatibility and infection resistance remain desirable.